1. Field of the Invention
The present invention relates to an automotive system which is composed of systems such as a car audio system and also to a method of controlling such an automotive information system, as well as to a storage medium that stores a control program. The present invention also is concerned with an information processing apparatus, an electronic device and a control unit that are suitable for use in the automotive information system. The present invention also pertains to a disk playback apparatus, as well as to a semiconductor integrated circuit, suitable for use in the automotive information system.
2. Description of the Related Arts
Car audio systems that are used on automobiles are known. Such a car audio system has a major function to provide audio information through a speaker mounted on the automobile, based on sound information acquired through a radio tuner, a cassette tape deck or a CD player. Current progress in the semiconductor technology has made it possible to combine with a car audio system various systems or apparatuses such as a car navigation system, a CD auto-changer or an MD auto-changer, cellular phone and so forth. In this specification, such a consolidated system will be referred to as “an automotive information system”, while systems or apparatuses combined with a car audio system will be collectively referred to also as “peripheral devices”.
Automotive information system of the kind described generally employs highly complicated wring layouts. For instance, a complicated wiring layout is necessary when a compatible auto-changer that is adapted both for music CDs and CD-ROMs is connected via cables to a main unit of the automotive information system that has a car audio function and car navigation function. The auto-changer reads sound data (audio data) from a music CD and reads also digital data such as car navigation program data and map data.
Hitherto, the connection between the main unit of the automotive information system and the auto-changer required. besides an electric power cable and control cables, an analog cable corresponding to a LINE-OUT terminal and an optical fiber for digital output that are used for transmission of audio data acquired from a music CD, as well as a digital signal cable which is used exclusively for digital data read from a CD-ROM and which is adapted to, for example, an ATAPI interface.
Despite the sophisticated and complicated wiring layout, the audio function and car navigation function of the known automotive information system are available only on an automobile and, therefore, have limited use.
Automotive information systems are also known of the type that has a microcomputer incorporated in the main unit of the system or in each of the devices constituting the system. Such microcomputers, however, are of a low grade that is intended only for controlling mechanical motions of the system or controlling display of characters. It is impossible to add new functions or modify existing functions on such microcomputers. In addition, control of supply of electrical power is possible only from the main unit to which cables and lines are concentrated. Namely, although supply of electrical power to peripheral devices is controllable from the main unit, no function is available for enabling one or more peripheral devices to turn on and off the power supply to the main unit of the system.